1. Field of the Invention
The present invention relates to a method of resolving (.+-.)3-(1-methyl-2-pyrrolidinyl)-2-pyridone (1) into (S)-(-)-3-(1-methyl-2-pyrrolidinyl)-2-pyridone (2) and (R)-(+)-3-(1-methyl-2-pyrrolidinyl)-2-pyridone (3).
2. Description of the Related Art
Nicotine is an alkaloid which can be obtained as a by-product in the tobacco industry and a derivative thereof is also known as a useful compound having an effect of improving the flavor and taste of tobacco (e.g., Jpn. Pat. Nos. 1371806 and 1456909). More specifically, it has been found that glycosides, which are composed of optically active nicotine derivatives (2) and (3) and glucose etc. binding thereto, are remarkably effective in improving the flavor and taste of tobacco. These derivatives (2) and (3) are not only important intermediates to produce the aforementioned useful compounds but also compounds whose own physiological activities are expected.
In order to synthesize the compounds (2) and (3), first, a racemic mixture of the compounds (2) and (3) are synthesized by use of a known method, and then the racemic mixture obtained must be optically resolved. However, the optical resolution method has a drawback in that the cost to produce the compounds (2) and (3) on an industrial scale is inevitably increased since an optically active column, which is a high-cost and requires a high dilution condition at a resolution process, must be used in this method.